A vacuum cleaner sucks the air containing impurities by a vacuum pressure generated by a vacuum motor installed in a main body, filters off the impurities in the main body, and collects and discharges the impurities.
The vacuum cleaner sucks the air containing the impurities through a suction nozzle portion. The position of the suction nozzle portion must be continuously changed to clean a large area space. The cleaning performance of the vacuum cleaner is lower on a carpet than a floor. That is, the vacuum cleaner cannot efficiently suck the impurities due to an adhesion force between carpet hairs and impurity particles.
Accordingly, a brush is installed at the suction nozzle portion of the vacuum cleaner, for lifting the impurity particles from the carpet hairs. As the suction nozzle portion having the brush separates the impurity particles from the carpet hairs by using the brush and sucks the impurities, it is advantageous in a drag coefficient. However, in the case of a power nozzle portion or a turbine type nozzle portion into which a brush is inserted, a suction passage is enlarged due to a large diameter of the brush. The power nozzle portion or the turbine type nozzle portion has a lower surface pressure than an ordinary type nozzle portion, and thus is disadvantageous in the aspect of the surface pressure generation.
FIGS. 1 and 2 illustrate a top surface and a bottom surface of a conventional ordinary type nozzle portion. Referring to FIG. 2, a vacuum channel 1 and a suction hole 2 are formed at the bottom surface of the suction nozzle portion. The suction hole 2 is positioned in a suction passage connecting a suction pump to the suction nozzle portion, and the vacuum channel 1 is extended from the suction hole 2 in the right-left direction, for defining part of the suction passage. Impurities of the surface contacting the vacuum channel 1 are moved with the air along the vacuum channel 1, and collected in a collection box in a main body of a vacuum cleaner through the suction hole 2. The vacuum channel 1, which is formed narrow and long, has a high surface pressure, and advantageously sucks the impurities from the floor. However, in the case of a carpet to which impurities stick, a sum of an adhesion force A and an impurity weight G is larger than a lifting force F. It is thus impossible to efficiently suck the impurities.
FIGS. 3 and 4 illustrate a top surface of a conventional brush type nozzle portion in which a brush 3 is installed. The brush 3 is rotated to separate impurities from a carpet. When a lifting force F is larger than a gravity G operated on the impurities, the impurities can be sucked. However, the brush 3 increases the whole size of the suction nozzle portion. Moreover, the brush 3 is rotated around a rotation shaft, to clean only a region which brush bristles rotation-contact. A region between the brush bristles is relatively poorly cleaned. Meanwhile, in order to rotate the brush 3, a motor is connected to the rotation shaft of the brush 3 through a transmission belt, for transferring a driving force to the rotation shaft of the brush 3. If the transmission belt is used for a long time, it is broken, and thus replaced. As a result, reliability of the product is reduced.